scholarly journals Quantum Information Remote Carnot Engines and Voltage Transformers

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 127 ◽  
Author(s):  
Jose Diazdelacruz ◽  
Miguel Martin-Delgado
Keyword(s):  
Quantum Information ◽  
Long Range ◽  
Physical System ◽  
Thermal Equilibrium ◽  
Heat Bath ◽  
Magnetic Interactions ◽  
Electrical Network ◽  
Heat Engines ◽  
Different Temperatures ◽  
Available Information

A physical system out of thermal equilibrium is a resource for obtaining useful work when a heat bath at some temperature is available. Information Heat Engines are the devices which generalize the Szilard cylinders and make use of the celebrated Maxwell demons to this end. In this paper, we consider a thermo-chemical reservoir of electrons which can be exchanged for entropy and work. Qubits are used as messengers between electron reservoirs to implement long-range voltage transformers with neither electrical nor magnetic interactions between the primary and secondary circuits. When they are at different temperatures, the transformers work according to Carnot cycles. A generalization is carried out to consider an electrical network where quantum techniques can furnish additional security.

scholarly journals Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

2011 ◽  
Vol 2 ◽  
pp. 552-560 ◽  
Author(s):  
Miriam Jaafar ◽  
Oscar Iglesias-Freire ◽  
Luis Serrano-Ramón ◽  
Manuel Ricardo Ibarra ◽  
Jose Maria de Teresa ◽  
...  
Keyword(s):  
Long Range ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Superparamagnetic Nanoparticles ◽  
Kelvin Probe Force Microscopy ◽  
Magnetic Interactions ◽  
Kelvin Probe ◽  
Force Microscopy

The most outstanding feature of scanning force microscopy (SFM) is its capability to detect various different short and long range interactions. In particular, magnetic force microscopy (MFM) is used to characterize the domain configuration in ferromagnetic materials such as thin films grown by physical techniques or ferromagnetic nanostructures. It is a usual procedure to separate the topography and the magnetic signal by scanning at a lift distance of 25–50 nm such that the long range tip–sample interactions dominate. Nowadays, MFM is becoming a valuable technique to detect weak magnetic fields arising from low dimensional complex systems such as organic nanomagnets, superparamagnetic nanoparticles, carbon-based materials, etc. In all these cases, the magnetic nanocomponents and the substrate supporting them present quite different electronic behavior, i.e., they exhibit large surface potential differences causing heterogeneous electrostatic interaction between the tip and the sample that could be interpreted as a magnetic interaction. To distinguish clearly the origin of the tip–sample forces we propose to use a combination of Kelvin probe force microscopy (KPFM) and MFM. The KPFM technique allows us to compensate in real time the electrostatic forces between the tip and the sample by minimizing the electrostatic contribution to the frequency shift signal. This is a great challenge in samples with low magnetic moment. In this work we studied an array of Co nanostructures that exhibit high electrostatic interaction with the MFM tip. Thanks to the use of the KPFM/MFM system we were able to separate the electric and magnetic interactions between the tip and the sample.

scholarly journals Long-range focusing of magnetic bound states in superconducting lanthanum

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Howon Kim ◽  
Levente Rózsa ◽  
Dominik Schreyer ◽  
Eszter Simon ◽  
Roland Wiesendanger
Keyword(s):  
Long Range ◽  
Bound States ◽  
Theoretical Calculations ◽  
Surface States ◽  
Magnetic Interactions ◽  
Magnetic Impurities ◽  
Natural Choice ◽  
Temperature Scanning ◽  
Quantum Mechanical Systems ◽  
Low Dimensional

Abstract Quantum mechanical systems with long-range interactions between quasiparticles provide a promising platform for coherent quantum information technology. Superconductors are a natural choice for solid-state based quantum devices, while magnetic impurities inside superconductors give rise to quasiparticle excitations of broken Cooper pairs that provide characteristic information about the host superconductor. Here, we reveal that magnetic impurities embedded below a superconducting La(0001) surface interact via quasiparticles extending to very large distances, up to several tens of nanometers. Using low-temperature scanning probe techniques, we observe the corresponding anisotropic and giant oscillations in the LDOS. Theoretical calculations indicate that the quasi-two-dimensional surface states with their strongly anisotropic Fermi surface play a crucial role for the focusing and long-range extension of the magnetic bound states. The quasiparticle focusing mechanism should facilitate the design of versatile magnetic structures with tunable and directed magnetic interactions over large distances, thereby paving the way toward the design of low-dimensional magnet–superconductor hybrid systems exhibiting topologically non-trivial quantum states as possible elements of quantum computation schemes based on Majorana quasiparticles.

TWO-TEMPERATURE NON-EQUILIBRIUM ISING MODELS

1996 ◽  
Vol 07 (03) ◽  
pp. 389-399 ◽  
Author(s):  
P. TAMAYO ◽  
R. GUPTA ◽  
F. J. ALEXANDER
Keyword(s):  
Ising Model ◽  
Computational Study ◽  
Heat Bath ◽  
Universality Class ◽  
Ising Models ◽  
Local Competition ◽  
Equilibrium Dynamics ◽  
Different Temperatures ◽  
Two Temperature ◽  
Non Equilibrium

We present results from a computational study of a class of 2D two-temperature non-equilibrium Ising models. In these systems the dynamics is a local competition of two equilibrium dynamics at different temperatures. We analyzed non-equilibrium versions of Metropolis, heat bath/Glauber and Swendsen-Wang dynamics and found strong evidence that some of these dynamics have the same critical exponents and belong to the same universality class as the equilibrium 2D Ising model.

scholarly journals Non-Equilibrium Liouville and Wigner Equations: Classical Statistical Mechanics and Chemical Reactions for Long Times

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 179 ◽  
Author(s):  
Ramon Álvarez-Estrada
Keyword(s):  
Orthogonal Polynomials ◽  
Chemical Reactions ◽  
Thermal Equilibrium ◽  
Three Dimensional ◽  
Liapunov Function ◽  
Heat Bath ◽  
Wigner Functions ◽  
Statistical Systems ◽  
Non Equilibrium

We review and improve previous work on non-equilibrium classical and quantum statistical systems, subject to potentials, without ab initio dissipation. We treat classical closed three-dimensional many-particle interacting systems without any “heat bath” ( h b ), evolving through the Liouville equation for the non-equilibrium classical distribution W c , with initial states describing thermal equilibrium at large distances but non-equilibrium at finite distances. We use Boltzmann’s Gaussian classical equilibrium distribution W c , e q , as weight function to generate orthogonal polynomials ( H n ’s) in momenta. The moments of W c , implied by the H n ’s, fulfill a non-equilibrium hierarchy. Under long-term approximations, the lowest moment dominates the evolution towards thermal equilibrium. A non-increasing Liapunov function characterizes the long-term evolution towards equilibrium. Non-equilibrium chemical reactions involving two and three particles in a h b are studied classically and quantum-mechanically (by using Wigner functions W). Difficulties related to the non-positivity of W are bypassed. Equilibrium Wigner functions W e q generate orthogonal polynomials, which yield non-equilibrium moments of W and hierarchies. In regimes typical of chemical reactions (short thermal wavelength and long times), non-equilibrium hierarchies yield approximate Smoluchowski-like equations displaying dissipation and quantum effects. The study of three-particle chemical reactions is new.

Kinetic paths of B2 and DO3 order parameters: Experiment

1989 ◽  
Vol 4 (5) ◽  
pp. 1140-1142 ◽  
Author(s):  
L. Anthony ◽  
B. Fultz
Keyword(s):  
Thermal Equilibrium ◽  
Nearest Neighbor ◽  
Order Parameters ◽  
Temperature Dependent ◽  
Critical Temperatures ◽  
Subsequent Evolution ◽  
X Ray ◽  
Rates Of Change ◽  
Temperature Dependences ◽  
Different Temperatures

Rapidly quenched powders of Fe3Al were subjected to thermal annealings at temperatures well below the critical temperatures for B2 and DO3 ordering. X-ray diffractometry was used to measure the subsequent evolution of B2 and DO3 long-range order. It was found that the relative rates of change of B2 and DO3 order parameters were temperature dependent; hence at different temperatures the alloy passed through different states of order en route to thermal equilibrium. These temperature dependences of “kinetic paths” can be understood in terms of a theory of kinetic paths based on the kinetic master equation. The theory indicates that the temperature dependence of the observed kinetic paths originates from having first-nearest-neighbor interactions that are stronger than second-nearest-neighbor interactions. This seems consistent with previous thermodynamic analyses of critical temperatures of Fe3Al.

Impact of short and long-range effects on the magnetic interactions in neutral organic radical-based materials

2013 ◽  
Vol 15 (18) ◽  
pp. 6982 ◽  
Author(s):  
Alex Domingo ◽  
Martin Vérot ◽  
Fernando Mota ◽  
Coen de Graaf ◽  
Juan J. Novoa ◽  
...  
Keyword(s):  
Long Range ◽  
Magnetic Interactions ◽  
Organic Radical

scholarly journals Publisher's Note: Long-range magnetic interactions in the multiferroic antiferromagnet MnWO4[Phys. Rev. B83, 140401(R) (2011)]

2011 ◽  
Vol 84 (17) ◽  
Author(s):  
Feng Ye ◽  
Randy S. Fishman ◽  
Jaime A. Fernandez-Baca ◽  
Andrey A. Podlesnyak ◽  
Georg Ehlers ◽  
...  
Keyword(s):  
Long Range ◽  
Magnetic Interactions
Sign in / Sign up

Export Citation Format

Share Document